BONENT CHN flashcards
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- Kt/V target
- A single-pool Kt/V of at least 1.2 per hemodialysis session given three times weekly; an equivalent urea reduction ratio of at least 65% also indicates adequate clearance.
- Intradialytic hypotension first steps
- Stop ultrafiltration, place the patient in Trendelenburg position, and give a saline bolus per protocol, then reassess blood pressure before resuming at a lower ultrafiltration rate.
- Saline bolus for hypotension
- Typically 100-200 mL of 0.9% sodium chloride is infused for symptomatic intradialytic hypotension; hypertonic saline may be used when cramps accompany the pressure drop.
- AV fistula assessment
- Palpate for a thrill and auscultate for a bruit; a pulsatile access without a thrill suggests inflow stenosis and should be reported before cannulation is attempted.
- Heparin dosing during dialysis
- A loading dose of roughly 1000 units followed by 500-1500 units per hour keeps the activated clotting time about 1.5-1.8 times baseline, preventing circuit clotting without systemic bleeding.
- High venous pressure alarm
- Rising venous pressure indicates outflow resistance such as needle infiltration, tubing kink, clot in the venous chamber, or dialyzer fiber clotting; inspect the access and circuit before continuing.
- Post-dialysis access hemostasis
- Apply firm pressure to both needle sites for 10-15 minutes without eliminating the thrill, then inspect for rebleeding and confirm hemostasis before the patient leaves.
- Normal glomerular filtration rate
- About 125 mL per minute, producing roughly 180 liters of filtrate daily; urinary output is far smaller because more than 99% of the filtrate is reabsorbed.
- Erythropoietin production site
- Peritubular interstitial cells of the kidney sense tissue hypoxia and secrete erythropoietin, which stimulates red blood cell production in the bone marrow.
- Aldosterone renal action
- Released by the adrenal cortex, aldosterone increases sodium reabsorption and potassium secretion in the distal nephron, expanding extracellular fluid volume and raising blood pressure.
- CKD stage 5 definition
- A glomerular filtration rate below 15 mL/min/1.73 m² defines stage 5 chronic kidney disease, the stage at which dialysis or transplantation is typically required.
- Secondary hyperparathyroidism cause
- Failing kidneys cannot excrete phosphate or produce calcitriol, so phosphate rises and calcium falls; these changes stimulate parathyroid hormone release and bone resorption.
- Antidiuretic hormone action
- Antidiuretic hormone released from the posterior pituitary inserts aquaporin channels in collecting duct cells, increasing water reabsorption and concentrating the urine.
- KoA of a dialyzer
- The mass transfer-area coefficient combines membrane permeability and surface area; a higher KoA means greater small-solute clearance at any given blood and dialysate flow rate.
- Ultrafiltration coefficient Kuf
- Expressed in mL per hour per mmHg of transmembrane pressure, Kuf describes how much fluid a dialyzer removes for each unit of pressure applied across the membrane.
- Countercurrent dialysate flow
- Blood and dialysate move in opposite directions through the dialyzer, preserving a concentration gradient along the entire membrane and maximizing solute removal.
- Air embolism response
- Stop the blood pump, clamp the venous line, position the patient in left lateral Trendelenburg position, and administer 100% oxygen while calling for emergency assistance.
- Pre-pump arterial pressure
- A negative pressure more negative than about -250 mmHg signals excessive inflow resistance from a kink, small or malpositioned needle, access stenosis, or low blood pressure.
- Dialysate conductivity range
- Dialysate conductivity normally measures about 13-14 mS/cm; values outside this range call for stopping treatment and verifying concentrate proportioning before resuming.
- Total cell volume reuse limit
- A reused dialyzer must retain at least 80% of its baseline total cell volume; a lower value indicates fiber clotting and reduced clearance, so the dialyzer is discarded.
- Chlorine testing frequency
- Total chlorine and chloramine in product water are tested before each shift and after carbon filter changes; the acceptable limit is below 0.1 mg/L.
- Carbon filter function
- Activated carbon removes chlorine and chloramine from feed water; an exhausted filter allows these oxidants into dialysate and can cause hemolysis and methemoglobinemia.
- Reverse osmosis function
- High pressure forces feed water through a semipermeable membrane that rejects 90-99% of dissolved ions, bacteria, and endotoxin, producing purified water for dialysate.
- Water softener function
- A softener exchanges calcium and magnesium for sodium to prevent scale formation; hardness is tested daily and the resin regenerated with brine solution.
- Bicarbonate dialysate separation
- Bicarbonate concentrate is stored separately from acid concentrate containing calcium and magnesium because combining them would precipitate insoluble calcium carbonate in the dialysate.
- Dialysate endotoxin limit
- Standard dialysate should contain fewer than 200 colony-forming units per mL of bacteria and less than 2 EU/mL of endotoxin; ultrapure dialysate standards are considerably stricter.
- Hepatitis B dialysis precautions
- Hepatitis B surface antigen-positive patients are dialyzed in a separate room or area with dedicated equipment, because the virus survives on surfaces and spreads easily within units.
- Hepatitis C machine assignment
- Hepatitis C infection is not an indication for a dedicated dialysis machine; standard precautions with hand hygiene, gloves, and careful disinfection are considered sufficient.
- Needlestick immediate actions
- Wash the exposed site with soap and water, report the exposure immediately, and arrange source testing; HIV postexposure prophylaxis is most effective when started within hours.
- Blood spill disinfection
- Visible blood spills are cleaned with a 1:10 dilution of household bleach, roughly 0.5% sodium hypochlorite, allowing adequate contact time before wiping the surface.
- Catheter hub connection care
- Both patient and nurse wear masks during catheter connection and disconnection, the hub is scrubbed with chlorhexidine and allowed to dry, and a sterile dressing is applied.
- Sharps handling rules
- Needles are never recapped, bent, or broken; the safety device is activated and the needle dropped directly into a puncture-resistant sharps container at the point of use.